Today’s lecture covers the topic of Distributed Cognition. Distributed Cognition builds on the tradition of Cognitive Science, which aimed to explain human cognition as computation. Distributed Cognition is a theory that looks at how cognition occurs not just in our heads, but also in the world. It applies the computational view of cognitive science to processes in the world. It differs from cognitive science in the following two respects:

• The unit of analysis is expanded from just being what goes on inside a person’s head to include the whole system that achieves computation.
• It expands the range of mechanisms assumed to constitute cognitive processes from mental processes to physical and social interactions.

Researchers working from a Distributed Cognition perspective have highlighted the role of the tools that people use, their social organization and their cultural context in cognition. Distributed cognition researchers look for the ways that cognition is distributed within a computational system. They identify three ways that it can be distributed:

• Across the members of a social group.
• Between internal and external representations.
• Through time, such that the results of earlier events can transform the nature of later events.

The basic attitude of Distributed Cognition could be summed up as:

Work is more than the activity of a single individual working alone and without tools.

The goal of Distributed Cognition is then to identify and explain the extra tools, resources, and social relations that people draw on to carry out their work.

Critical Questions

• Distributed Cognition makes no distinction between people and artefacts. Both are treated as ‘media’ that hold and transform representations. Therefore, as Nardi remarks, “Messy cognitive activities conducted every day by ordinary humans, such as interpretation and imagination, are difficult to consider within such a framework.” (Nardi 2002, p.273)
• Is computation an appropriate metaphor for understanding all people’s activities?

Practical Task

Your task for this week is to analyse the activities that occur in the Library in the terms of Distributed Cognition. In groups of two or three, first identify a ‘cognitive process’ in the library. Observe people engaged in this process and attempt to map it out. See if you can:

• Map ‘information flows’
• Find out how information is represented and transformed.
• Find ‘cognitive artefacts’ or other concepts from this week’s lecture and readings.

You should prepare a short (5-10 minutes) presentation of the results of your interview for next week’s class.

Slides

Lecture slides are available.

Readings

• Hollan, J., Hutchins, E., and Kirsh, D. “Distributed Cognition: Toward a New Foundation for Human-Computer Interaction”, ACM Transactions on Human-Computer Interaction, Vol. 7, No. 2, June 2000, pp 174-196.
• McGarry, B. Extract from “Things to Think With” Unpublished PhD dissertation, the University of Queensland. 2005, pp 34-45
• Nardi, 2002. Coda and Response to Christine Halverson. Computer Supported Cooperative Work (CSCW), 11(1), p.269-275.

Web Resources

• UCSD DCOG and HCI Laboratory: This lab is mentioned in the ‘Hollan’ reading. Home to prominent researchers in the area and has links to some publications.
• Critique of Distributed Cognition: written by a student as part of a course similar to this one.
• Wikipedia article: Overview article with links to related theories.

Yesterday my hosting company upgraded the software library that I use to allow OpenID logins to stikis. Unfortunately, this new version was not compatible with the version I have been using previously. This resulted in errors for users trying to log in using OpenID identities.

To fix the problem, I have ‘frozen’ the library I use to the last compatible version.

Apologies to any users who were affected by this.

Our research group was fortunate to succeed in our application for money to upgrade our video equipment. Now the question is, what should we buy?

A recent discussion on the AnthroDesign list covered a similar topic. People there emphasized the importance of:

• Ability to film in low light
• Battery duration
• Storage capacity
• Ergonomics (grip etc.)
• Audio quality, the ability to attach an external mic.
• Wide angle lens.
• Extended warranty that covers wear, since it’s likely that we will wear cameras out.
• 10x optical zoom.
• Image stabilization. OIS or EIS. OIS is preferable.
• Headphone jack for sound monitoring when using external microphones.

Which Format?

Now is probably a good time to move from standard to high definition video. HDV is the best high definition format for our needs.

The most common recording format now is DV. This is a standard definition format. It is what all our current camcorders use. It is easier to edit on computers, takes less space, and the camcorders are cheaper. However, it is a lower resolution and will likely be superseded.

Currently, there are two main options for high definition recording. These are HDV, and AVCHD. AVCHD is a newer format. It uses a different compression algorithm that can fit more data in a given space while maintaining comparable image quality. The trade-off is that working with the format requires more computer power and is supported by fewer video editing programs. For our purposes, HDV would probably be the better choice.

MiniDV tape is probably the best storage medium for us. Camcorders are now being made with a variety of storage media. In addition to tape-based camcorders, you can buy ones that will record to hard-disk, flash memory or recordable DVD. The newer formats promise to make it simpler to transfer movies from the camcorder to computer and offer the possibility of non-linear access, but these are not so important for our needs. In fact, transferring movies recorded in AVCHD format to be edited in iMovie is still very time consuming, because they need to be transcoded to another compression format. For 60 minutes of video, this transcoding process can take 2 hours or more. Another consideration is that whereas archival ‘just happens’ with tape recording, it takes an extra effort for these other media. Tape is cheap and readily available enough that students can buy their own tapes as they need them.

How will we use them?

We should also consider what we will use the cameras for. Despite the disadvantages of hard disk, or flash disk based camcorders for archival purposes. For making a short video presentation that we are going to share on the web, they are probably very convenient. Here are some suggestions for what we might want to use the cameras for:

• Student projects.
• Field work.
• Workshop recordings.
• Project documentation.
• Vodcasts/Podcasts.
• Taking still photographs (can be useful but not a replacement for a still camera).

Other considerations

• How do we store and manage access to them?
• Additional hardware - batteries, tripods, external microphones?
• Equipment for audio-only recordings?

Links:

One of the posts on the AnthroDesign discussion provided these links. I thought they were quite interesting.

• NYTimes article on the cons of moving away from tape as a storage medium.
• Blog post about high speed cameras, including one soon-to-be-released from casio.
• Article from popular mechanics describing the parts of a camcorder and what one can expect in different price brackets.

I’ve also been looking at the following camcorder review site (I’m sure there are plenty of others.)

• www.camcorderinfo.com

Candidate: Canon HV30

Review page from January 2008.

This is an update to the HV20, which was released in 2007. That camera was voted best something of the year by the camcorderinfo site (Review page from March 2007). The price is somewhere around $1000 USD.

• Pros: 24P, 30P (need to check for compatability). Good in low light. MiniDV tapes. HDV format. External microphone jack. Analog to digital conversion ability. Hot accessory shoe.
• Cons: Awkward controls. Difficult to hold. Crappy built-in light.

We had a discussion of the idea of Mental Models that was presented in the previous lecture. We first took a round where each of the groups gave a presentation of their results from the practical exercise. The exercise was to find evidence for mental models in the way that people use interactive products.

Six groups gave presentations on the following topics:

• Mobile Phone: How to find the calendar function on an unfamiliar phone.
• Mobile Phone: Taking a picture with the phone camera and setting it as the background image. Sending an SMS message.
• Digital Camera: Exploring the functions of an unfamiliar digital camera.
• Mobile Phone: Sending a message as well as the general understanding of the phone.
• Dishwasher: Differences in the ways that men and women think of what happens after you press start.
• Microwave: How different people think the microwave works.

We then looked back over some of the questions raised in last week’s lecture and discussed them in relation to the results of the practical task.

Kinds of mental model

The four kinds of mental model identified by Carroll & Olson (1988) and presented in the lecture were:

• Surrogate: A model that mimics the output of a system, but not the internal workings.
• Metaphor models: You understand a product by comparing it to something else that you already know.
• Glass Box models: Somewhere between a surrogate and metaphor model. A composite of different metaphors that together can describe the system.
• Network representations: Understanding a product as a series of states with transitions between them.

Students from each group tried to say which of these models characterized the kind of models they had seen. The white-board on the right side of the picture above shows what we ended up with. All groups found that their examples contained bits and pieces of different categories. It didn’t seem that there was one way that people thought about the products, but rather a combination of different ways.

There was also a discussion of where a correct model would be put, if we had one. We wondered how one would determine if a model was correct or not and supposed that this determination would depend on criteria of the person holding the model. Therefore it’s probably not possible to single out one model as the correct one.

Staged model of human action

We discussed whether the people the students had interviewed had seemed to act like the staged model of human action presented in the lecture. Students suggested that when people are asked a question that they have to think about, or when they are presented with an unfamiliar situation that it might be like this. There was also an example from the practical task where the person interviewed had gone into trial and error in his attempt to get the mobile phone to work. Perhaps a trial and error kind of activity would fit with this model. We also discussed that not all the levels in the model are processes that we are conscious of.

How do we find out about mental models?

Groups had gone about interviewing people to find out about their mental models in a variety of ways:

• Asking in general how a product works (Microwave, Dishwasher).
• Give a product to the person and ask them to use it (Phones, Camera).
• Set a specific task for the person to do (Phones).
• Ask the person to explore the interface and explain what they are doing (Camera).
• Interview just one person, or several.

Was any of the information gained useful for design?

Does the mental model theory help us as designers? We asked whether there information had emerged from the practical task that could be useful for improving the products studied. Students made the following suggestions:

• You can see what is important to people. This could be used to improve the organization of the camera menus for instance.
• It could provide an argument for further user involvement in the design process. If you could take ‘mental models’ of prospective users back to an organization, it might help convince them that users sometimes see their products in different ways.
• You could remove unnecessary programs. In the dishwasher, it seemed that few people used the settings of the dishwasher beyond choosing an automatic program.
• Understanding the mental model could be used to make a product more consistent, or alternatively to make it more unpredictable (e.g. in a game). In the second case, a designer might still find it useful to be aware of the likely mental model of users so that they can make the product to unpredictable things. There is also a tension between the desire for a consistent model, and the differences between how different people conceive of products.

Did we find a mental model?

My own feeling is that there didn’t seem to be a clear case of a mental model in any of the presentations beyond what one might characterize as just knowledge about how things work.

We didn’t see much evidence in the presentations of how people’s product use related to their social or professional circumstances or to the physical environment. As we will see in future classes, these are all areas that other theories in HCI have paid more attention to and shown to be important. Maybe the focus on mental models in this practical task lead us to overlook these.

An intriguing result of the practical exercise was that students in several groups not only found out about how people conceive of a product (their mental model) but also some strategies they use when trying to figure it out. Examples were, ‘getting an overview’, ‘trial and error’ and ‘relying on the preset routine’. These ‘use strategies’ seemed an important part of how people used the products, but aren’t addressed by the theory that people have mental models.

However, the notion of mental models did seem useful to the students in how they organized and went about the task. It seemed to give them a worthwhile objective to inquire after. It also seemed to provide a common language for ho we discussed people’s use of the products.

Today’s lecture covers the topic of ‘Mental Models’. This has been a long standing and influential idea in Human Computer Interaction. The basic idea is that people have internal mental models of the way a system works and they use these models to help them when they use a system. One possible application of this idea for designers is that by designing our systems so that the working of the system is clear in the interface, it is easier for users to form a useful mental model of the product.

Critical Questions

The idea of Mental Models is often appealing to designers because it seems to make sense and offer practical and useful insights into the way users interact with products. However, there are some critical questions you should consider also.

• Do people really have Mental Models? What separates a Mental Model from everyday knowledge?
• Focusing on mental representations can divert attention from the many other resources people use to help them when using interactive products. What about other people, or physical resources?
• How much does this actually help designers? Does it change the problem of design to the problem of uncovering the correct model?

Practical Task

Your task for this week is to see if you can find evidence for Mental Models in the way people use interactive products. In groups of two or three, decide on an interactive product to investigate. The product could be anything from a web-page, to a mobile phone, to an elevator. Find a user of this product and interview them to find out how they understand the system to work.

Ask the person to show you how they use the product. Ask them to explain what they are doing as they use it. Try stopping them from time to time and asking what the think the product will do (and why) before they make an action. Then when they take the action, ask them if the response of the product matches their expectations.

You should prepare a short (5-10 minutes) presentation of the results of your interview for next week’s class. It doesn’t need to be anything fancy, but you should try to make a diagram, picture, or short description that sums up what you think the person’s mental model was. If you don’t think the person had a mental model - that’s also a good result. You should show instead the other resources they used to help them interact with the product.

Slides

Lecture slides are available.

Readings

There are three readings for the topic of mental models. Copies of the first two will be handed out in class.

• Carroll, J and Olson, J. “Mental Models in Human-Computer Interaction” in Handbook of Human-Computer Interaction, M Helander (ed), Elsevier, 1988.
• Payne, S. “Users’ Mental Models: The Very Ideas” in HCI Models, Theories, and Frameworks, Carroll, J. (ed) Morgan Kaufmann, 2003.
• Norman, D. “The Psychology of Everyday Things”, Basic Books, 1988. Chapter 1.

Web Resources

A search on ‘mental models’ will turn up many articles, blog entries, etc. Here are three that I browsed and found informative:

• What’s Your Idea of a Mental Model - Article at ‘boxes and arrows’, a usability blog. Well written article with some interesting comments.
• Mental Models - Annotated list of resources on the topic.
• Wikipedia article - short, but it has links to related topics and researchers in the area that might be of use.